Contact-board for rheostats



(No Model.) 2 Sheets-Sheet 1.

S. H. SHORT. `GONTJMJVI BOARD FOR RHEOSTATS. No. 467,613. Patented Jan. 26, 1892.

m: uunms ravens co., Preuve-umu., wAsmNsfoN. n. c.

` 2 Sheets-Sheet 2.

(No Model.)

S H SHORT CONTACT BOARD FOR RHBGSTATS.

FIGNII.

/ gli F IGXV UNITED STAT-Es PATENT OFFICE.

SIDNEY II. SHORT, OF CLEVELAND, OHIO.

CONTACT-BOARD FOR RHEosTATs.

SPECIFICATION forming part of Iietters Patent No. 467,613, dated January 26, 1892. Application filed March 18, 1891. Serial No. 385,549. (No model.)

To aZZ whom it may concern.-

Be it known that LSIDNEY-I-I. SHORT, of Cleveland, in the county of Cuyahoga and State of Ohio, have invented certain new and useful Improvements in Contact-Boards for Electric-Car Rheostats; and I do hereby de-v clare the-followin g to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates more particularly to the contact board or switch for connecting in the resistances or the like on' an electric-motor car; but each of the improvements constitutin g said invention is included for all the uses to which it may be adapted. A

The invention consists in certain particular constructions, combinations, and arrangements of parts, which can most conveniently be explained with the aid of the accompanying drawings.

Figure I is an elevation of a contact--board constructed in accordance with the invention. Fig. II is a plan view vof the same. Figs. III and IV are central sections looking in opposite directions, and Figs. V to XVIII are dcp tail views.

The base A of the contact-board is of laminated wood--that is to say, of different layers of wood, with the grain running in difterent directions; but a base4 otherwise constructed may be `used with the other devices. The bodies of the contacts B are raised above the non-conducting base A and are separated from each other by air-spaces, so that the body of the contact is surrounded by air, which acts as a cooling medium. Such raised contacts may of course be made in different Ways. As shown, they each have feet 2 and 3 and a lug 4, by which they are held to the base A, and are provided, also, with a binding-post 5. By this construction the contacts are as rigid as if they were made of a solid block, being entirely inelastic by reason of the bearing-feet 2 3, one at each end of the block, and at the same .time the wholebod y of the contact proper is surrounded by air. In this respect my contact-blocks are different from contact-blocks made in the shape of brackets secured at one end only, which, al- 5o though vsurrounded by air, are liable to be bent and thus miss contact with the switch- EtI'Il'l.

The switching-arm C has a long hub 6,which turns loosely on a pin D, said pin being supported in a casting E, which has a plate 7 and a binding-post 8 and is fastened to the base A. There is also a stop 9 on the casting E. This stop 9 is a lateral extension from the plate 7, integral with the same, and is bent 6c upward into the path of one branch CX of the switch-arm C. The branch CX of the switcharm. is curved downwardly, so that its free end may strike against the stop, while the arm Cis left straight, so as to clear that stop. The arm Ck, opposite the switching-arm C, strikes said stop when the switch-arm has been turned sufficiently in the direction opposite to the movement of the hands of a watch.

As shown, the arm C* is against a` stop 10, 7o

which limits the movement of the switchingarm in the opposite direction. The switching-arm C is turned by a sprocket-wheel F, fast on the hub 6, or by other suitable means.

A rubber of any suitable description might be used to travel over the contacts B; but that shown is of improved form, and consists of a number of plates 11, turned 'edgewise and held down by the pressure of a spring or springs 12. The end of the arm C is raised 8o at 13 (see Figs. VII and VIII) to receive the plates, which are pivoted on the pin 14, the holes in said plates (see Fig. XII) being elongated Widthwise of the plates 11, so that said plates may move bodily in adirection transversely of said pinli. The platesare adapted to catch against the raised part 13 when they are not held up by contacts B.

The resistances are connected electrically by suitable conductors with the contacts B, 9o and the ends 16 and 17 of the circuit which is to include them, are connected respectively, with the contact B and the casting E. By turning the arm C, therefore, the rubber 11 makes contact with the contacts B in suc- 95 cession and connects in more of the resistanccs until it leaves the last contact, in doing., which it breaks the circuit. After this has The arm C* is utilized to make connection with this contact G when the arm C is on the contact B', although it is not essential thatl the same arm should strike both the stops 9 and 10 and also make electrical connection with the contact G; nor is it essential that there should be two arms, one,as Cf, to make contact with the contact G and the other to sweep over contacts B.

It is desirable that the motor-man should put forth a special effort in order to bring the arm C* onto the contact G. To effect this object the pin D is movable lengthwise in the casting E and is held down by means of a spring H, (shown as a spiral compressionspring,) and a cam K is provided in the path of the arm C, so that when the latter strikes saidcam it is obliged to slide up its inclined surface 1S, (see Fig. XV,) lifti-ng the arms O C* and pin D against the resistance of the i spring H. After the arm C* has been lifted it passes onto the contact G. The contact B is provided with an incline at 19 (see Figs. II and III) and with a surface raised above the rubbing-faces of the other contacts The rubber 11 makes contact with this face when the arm Gif is on the contact G, which is the position shown in Figs. I to 1H. 4The contact B is elevated above the bearing-faces of the other contacts B, because at the time the rubbers 11 engage the contact B the arm C* also engages the elevated facial contact G, the spring H being compressed at this phase of operation to apprise the operator by the special effort required for this purpose that all resistance is being cut out and the special contact with the shunt or branch is being established. By reference to Figs. XII and XIII it will be seen that each lamina of the rubber 11 is formed on 4one side with a raised rim 11 around the elongated pivotal hole or slot by which the laminaeJ are strung upon the pin 14. By this construction the laminas of the rubber are separated from eachother by air-spaces, similar in this respect to the contacts B, and for the same purpose-viz., for cooling the body of the rubber. The laminze of the rubber are also curved laterally to correspond to the circle in which they travel, as shown in Fig. XIII, and by this construction I am enabled te utilize the whole edge 112 of each lamina as a bearing or rubbing surface, thus insuring great ease of movement, together with good contact and low resistance at the same time.

L I Iaving fully described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a contact-board for rheostats, the combinationvith a board, of a series of contacts separated from each other by air-spaces, each contact being constructed with a downwardlyprojecting foot at its opposite ends, whereby the body of the contact is elevated and separated from the board and an air-space is formed between them, substantially as set forth.

2. In a contact-board for rheostats, the co mbination, with a board, of a series of contacts separated from each other by air-spaces, each contact being provided at its inner end with a downwardly-projecting foot having a laterally-projecting flange by which it is secured to the upper surface of the contact-board, while the outer en'd of each contact is .provided with a downwardly-projecting foot adapted to .be secured to the outer edge of the contact-board, said contacts being arranged and secured inplace to form an air-space between the board and the body of the contact, substantially as set forth.

3. A contact-board provided with a semicircular series of contacts separated by airspaces from each other and from the board, in combination with a rubber or brush composed of laminre curved in the circle of their travel and separated from each other by airspaces, substantially as described.

4. A contact-board provided with a series of contacts separated by air-spaces from each Vother and from the board, in combination with a rubber or brush composed of laminte having holes elongated widthwise of the laminze, a common pivotal pin passing through the holes, and springs bearing upon the brush to force it against the contacts, substantially as described.

5. A contact-board provided with a series of rigid contacts, a pivoted switch-arm, a pivoted sprin g-actu ated rubber or brush mounted in the switch-arm, a spring for forcing the rubber or brush against the contacts, and an inclined surface or cani for raising .the arm against the opposing force of the spring, substantially as set forth.

G. A switching-arm having a raised part `and provided with the plates mounted onedge and having therein holes elongated widthwise of said plates, the pivot-pin passing through said holes, and the springs, substantially as described.

7. The combination, with the switchingarm, the series of contacts, and the special contact, of the spring and the cam whereby the said arm is lifted against the force of said spring in establishing the electrical connection with said special contact, substantially as described.

8. A contact-board comprising a non-conducting base, a series of contacts, a special contact thereon, a eastin g on the base, a switch- IOO IIO

arm turning on a pin in said casting, a spring on said pin, a Cam for lifting the pin and switch-arm against the action of the spring, and stops for limiting the movement of the switch-arm in either direction, substantially as described.

In testimony whereof I have signed this specification in the presence of two subscribing witnesses.

SIDNEY H. SHORT.

Witnesses:

E. H. MORRISON, A. B. CALHOUN. 

